Pressure responsive element of the wafer type



Sept. 22, GlARD PRESSURE RESPONSIVE ELEMENTS OF THE WAFER TYPE FiledJan. 15, 19:58

Patented Sept. 22, 1942 2,296,435 rnsssuas nssg ggsrvi: ELEMENT or runEBTYP Eugene Armand Giard, deceased, late of Milwaukee, Win, by BeatriceL. Giard, special administratrix, Milwaukee, Wis., assignor to Cutler-Bammer, Inc., Milwaukee, Wis., a corporation of Delaware ApplicationJanuary 15, 1938, Serial No. 185,147

8 Claims.

This invention relates to pressure responsive elements of the wafer typeand to a method of making the same.

The application of C. W. Kuhn et al., Serial No. 157,988, filed August'7, 1937 now Patent No. 2,245,691, dated June 17, 1941, discloses anoperating mechanism for refrigerator controllers including a gascontaining element of the wafer type. Such element meets variousrequirements, as for example the same is of small diameter, sensitive,capable of movement through a relatively wide range, capable ofsupplying a substantial operating force, capable of functioning smoothlyand with uniformity, and able to withstand many operations daily over aperiod of many years. To meet these requirements the wafer element hasvarious novel structural features, and this invention involves certainof these features.

The accompanying drawing illustrates an embodiment of the inventionwhich will now be described, it being understood that the embodimentillustrated is susceptible of modification without departing from thespirit and scope of the appended claims.

In the drawing:

Figure 1 is an enlarged side elevational view of a wafer elementembodying the invention, a cup-shaped support associated with theelement being shown in section;

Figs. 2 and 3 are enlarged plan views of solder rings which are employedin making the bellows shown in Fig. 1;

Fig. 4 is an enlarged sectional view illustrating the parts of the waferelement assembled for soldering, and 1 Fig. 5 is a greatly enlargedsectional view of a portion of the wafer element.

Referring to Fig. 1 the same illustrates a wafer element I having a pipeextension 2 which terminates in a gas-filled bulb portion 3 preferablyof the spiral form illustrated, although it may assume other forms. Asshown the wafer element also has a cup-shaped support 4 fixed thereto.

The wafer element l in a broad sense is of a well known form, but thesame differs essentially from expansible-wafers heretofore employed indevices of various types. It is designed for use in connection withrefrigerator control devices and in order to meet the variousrequirements hereinbefore noted the same must be formed of very thinsheet metal parts and provided with joints which are exceedingly strongand durable.

imperative to join the parts of the wafer element with silver solder andthe problem is then presented by applying sufflcient heat to melt suchsolder without warping or otherwise impairing the thin sheet metalparts. In accordance with the present invention the wafer element isprovided with oppositely disposed circular cupshaped elements 5 and 6which are formed of partially annealed fine grain beryllium copper sheetof a thickness of about .005 inch. It has been found that such materialis capable of withstanding the heat required for hard soldering withoutbecoming warped or otherwiseimpaired, and is also desirable for otherreasons.

Cup element 5 is formed to provide an outwardly extending flange 9 whichis disposed at right angles to the axis of said element and said elementis also formed to provide a circular flange l0 which surrounds saidformer flange and is disposed at right angles with respect thereto. Cupelement 6 has an outwardly extending flange II which is disposed atright angles to the axis thereof and said flange is of slightly lessdiameter than the inside diameter of flange l0 on element 5.

Cup element 6 is also provided with a center opening for receiving ahollow cylindrical nipple I2 formed of drawn brass tubing and having anopening in one end thereof for receiving the tube 2 and an outwardlyextending circular flange l3 on the opposite end thereof. Nipple I2 isslightly tapered to facilitate insertion thereof into the opening in cupmember 6 and the same is provided with a surrounding groove I4 adjacentflange l3 for receiving the inner edge of said cup element. Flange I3 isshaped to provide an annular shoulder l5 and the diameter of nipple I2is such that when cup element 6 is sprung over said shoulder as shown inFig. 5 the inner edge of said element is driven into the groove l4.

Referring now to Figs. 2 and 3 the same illustrate soldering rings l6and H, the former being employed for soldering the joint between cupelements 5 and 6, and the latter being employed for soldering the jointbetween cup element 6 g and nipple l2. Solder ring it is of suchdiameter It has been found that it is very desirable if not 5 as to fitsnugly within flange III on cup element 5 and the same consists of-twoparts a and 12, each of which is weakened at a plurality of sp cedpoints by notches l8. As is apparent the notches I8 render the solderring l6 relatively flexible at a plurality of points to facilitateengagement of said ring throughout its entire circumference with theinner surface of flange l0. Also during soldering the weakened portionsof ring I6 adjacent the notches l8 melt prior to the other portions tothereby prevent warping of said ring.

Solder ring I1 is of such diameterv as to sn y- 5 so that flange restsupon flange 9 and the parts are then sprayed with a suitable liquidflux. Solder rings I6 and ll a renext placed in position, care beingtaken to insure engagement 1 of ring "5 with flange H on element 6 andengagement of ring I! with the inner margin of said element. The partsare again sprayed with the liquid flux and then baked to dry the flux.

The joints of the wafer element are soldered simultaneously, in asoldering device, which does.

not enter into this invention. The soldering device employed is providedwith a pair of horizontally arranged ring shaped heater elements l9 and29 illustrated in dotted lines in Fig. 4. The wafer assembly is insertedwithin the soldering device with its nipple I2 extending upwardly andduring soldering the assembly is maintained with its axis in a verticalposition. Upon insertion of the wafer assembly within the solderingdevice, heater element l9 closely surrounds flange l0 and heater element20 closely surrounds nipple I2 and is located adjacent the soldenringII.

Under the action of heater elements l9 and 20 the solder rings 16 and Hare melted simultaneously and within a relatively short interval withoutundue'heating of the cupped portions I2 and said casing isv secured tosaid nipple by striking the metal of the sleeve inwardly at a of waferelements 5 and 6. The solder of ring I5 adheres to the inner surface offlange"! and is also drawn inwardly'by capillary attraction between theflanges 9 and II. As is apparent from Fig. 5 the flanges 9 and I I arethus connected bya continuous ring of hard solder to provide a verystrong and durable joint with but slight increase in the diameter of thewafer as compared with the diameter of the cup portionand'withoutstiffening of either cup portion by a flow of solder inwardly beyond theflanges 9 and H. Solder ring I! when melted adheres to nipple l2 and tothe inner marginal portion'of, cup element 6 to form a continuous ringof solder between the inner edge of said, element and nipple I 2.

After soldering the wafer element is heat treated to harden theberyllium bronze cup elements 5 and 6. The same is then thoroughlycleaned and tube 2 is soldered to nipple l2, a small ring of hard'soldersuch as silver being used for this purpose. The bellows assembly is thenevacuated and filled under pressure with a suitable fluid, as forexample methyl chloride, and after filling the outer end of tube 3 issealed and the entire unit is plated for protection against corrosion.

The joint between cup element Sand nipple l2 would not be durable ifleft unprotected, and for Thus flexing of the 'cup' 'elementfi islimited to points spaced from the number of points circumferentiallythereof as shown at 24 in Fig. 1.

. What is claimed as new and desired to be secured by Letters Patent is:

1. An expansible wafer comprising two circular cupped elements of thinsheet metal having peripherally thereof a continuous soldered jointlying in a plane from which the cup portions of said elements project inopposite directions, one of said elements having its marginal portionformed to provide a radially extending flat annulusland a ringupstanding from such annulus and the other element having. its marginalportion formedto provide a radially extending 'flat annulus to fitwithin said upstanding ring of the former element, said soldered jointcomprising said marginal portions of said elements and solder bondingtogether the inner surfaces of the annuli of said elements, the waferexterior surfaces contiguous to said annuli being free of solder andsaid ring being permanently upstand- 2. An expansible wafer comprisingtwo circular'cupped elements of thin sheet metal having peripherallythereof a continuous soldered joint lying in a plane from which the cupportions of said elements project in opposite directions, one of saidelements having its marginal portion formed to provide a radiallyextending flat annulu's. and a ring upstanding from such annulus and theother element having its marginal portion formed ,to provide a radiallyextending flat annulus to fit within said upstanding ring of the formerelement, said soldered joint comprising said marginal portions of saidelements and solder bonding together the inner surfaces of the annuli ofsaid elements, and also bonding to said inner surface of the ring theouter surface of the annulus inserted into said ring, the wafer exteriorsurfaces contiguous to said annuli being free of solder and said ringbeing permanently upstanding.

3. An expansible wafer comprising two circular cupped elements of thinsheet metal having peripherally thereof a continuous soldered jointlying in a plane from which the cup portions of solder joint and theclamping parts are curved to insure against sharp curvature of said ele-4. A gas containing wafer comprising two cir-- said elements project inopposite directions, one of said elements having its marginal portionformed to provide a radially extending flat annuannulus of the secondmentioned element to the, ring of the other element, the wafer exteriorsurfaces contiguous to said annuli being free of solder and said ringbeing permanently upstandcular cupped elements of thin sheet metalhaving peripherally thereof a continuous soldered joint lying in a planefrom which the cupped portions of said elements project in oppositedirections, one of said elements having its marginal portion formed toprovide a radially extending flat annulus and a ring upstanding fromsuch annulus and the other element having its marginal portionformed toprovide a-radially extending fiat annulus to fit within said ringof theformer element, said soldered joint comprising said marginal portions ofsaid elements and a ring of solder bonding the exposed peripheral edgeof the annulus of the second mentioned elementto the ring of the otherelement, said soldered ring also extending between the inner surfaces ofthe annuli of said elements, the spacing of said surfaces being such asto afford flow of the solder by capillarity between said annuli, thewafer exterior surfaces contiguous to said annuli being free of solderand said ring being permanentlyupstanding.

5. A gas containing wafer comprising two circular cupped elements ofthin sheet metal having peripherally thereof a continuous soldered jointlying in a plane from which the cupped portions of said elements projectin opposite directions, one of said elements having its marginal portionformed to provide a radially extending flat annulus and a ringupstanding from such annulus and projecting beyond said soldered jointand the other element having its marginal portion formed to provide aradially extending flat annulus to fit within said ring of the formerelement, said soldered joint comprising said marginal portions of saidelements and a ring of solder bonding the exposed peripheral edge of theannulus of the second mentioned element to the ring of the otherelement, said soldered ring also extending between the inner surfaces ofthe annuli of said elements, the spacing of said sur-.

faces being such as to afford flow of the solder by capillarity betweensaid annuli, and said annuli being of a breadth suflicient to preventflow of solder onto the cupped portions of said elements.

6. An expansible wafer comprising a cupped disk and a cupped annulus,both of thin sheet metal and having peripherally thereof a continuoussoldered joint, and a nipple with which said annulus has a continuoussoldered joint,

said nipple having a cylindrical portion termi-' nating in an annularend flange forming an abutment for said annulus which permits thecentral portion of said annulus to be sprung inwardly along said nippleand said cylindrical portio'nof said nipple having adjacent its juncturewith said flange an encircling groove receiving the edge of the innermarginal portion of said annulus when said annulus is sprung inwardlyalong said nipple, the solder of said joint between said nipple andannulus bonding said elements externally and extending into said groove.

7. An expansible wafer comprising a cupped disk and a cupped annulus,both of thin sheet metal and having peripherally thereof a continuoussoldered joint, a nipple for said annulus having a cylindrical portionterminating in an annular end flange forming an abutment for saidannulus which permits the central portion of said annulus to be sprunginwardly along said nipple, said cylindrical portion of said nipplehaving adjacent its juncture with said flange an encircling groove intowhich the edge of the inner marginal portion of said annulus is drivenwhen said annulus is sprung inwardly along said nipple, said inwardlysprung portion of said annulus forming with said nipple an external.circular groove, and a continuous solder ring formed in said groove tojoin said annulus and nipple,

8. An expansible wafer comprising a cupped disk and a cupped annulus,both of th n sheet metal and having peripherally thereof a continuoussoldered joint, a nipple for said annulus having a cylindrical portionterminating in an annular end flange forming an abutment for saidannulus which permits the central portion of said annulus to be sprunginwardly along said nipple, said cylindrical portion of said nipplehaving adjacent its juncture with said flange an encircling groove intowhich the edge of the inner marginal portion of said annulus is drivenwhen said annulus is sprung inwardly along said nipple, said inwardlysprung portion of said annulus forming with said nipple an external cir-

